Steam-engine



(No Model.) 6 Sheets-Sheet 1.

M. 0. BULLOCK. STEAM ENGINE.

No. 580.153. Patented Apr. 6, 1897.

(No Model.) 6 Sheets-Sheet 3. v

M. O. BULLOCK.

STEAM ENGINE.

No. 580,153. I Patented Apr. 6, 1897.

(No Model.) 6 Sheets-Sheet; 4.

M. O. BULLOCK. STEAM ENGINE.

No. 580,153. Patented Apr. 6, 1897.

was no. woroqrua. wsuwamu. u, c.

M. C. BULLOCK.

6 Sheets-Sheet 5.-

STEAM ENGINE.

(N0 lodel.)

No. 580,153. Patented Apr. 6, 1897.

fiwakgg g w w 15g K. *S Q Q QQ N k n n ms PETERS ca. PHmuLn-u (NoModel.) 7 I 6 Sheets-Sheet 6.

M. G. BULLOCK.

STEAM ENGINE.

Patented Apr. 6, 1897.-

Q Q0 Q0 UNITED STATES PATENT OFFICE.

MILAN C. BULLOCK, OF CHICAGO, ILLINOIS.

STEAM- ENGINE.

SPECIFICATION forming part of Letters Patent No. 580,153, dated April 6,1897'.

Application filed June 28, 1894.

To all whom, it may concern;

Be it known that I, MILAN C. BULLOCK, of Chicago, in the county of Cookand State of Illinois, have invented certain new and useful Improvementsin Steam-Engines; and I do hereby declare that the following is a full,clear, and extact description thereof, reference being had to theaccompanying drawings, and to the letters of reference marked thereon,which form a part of, this specification.

This invention relates to improvements in that class of compound enginesin which the high and low pressure pistons are each single acting orsubjected to steam-pressure on one side only, but are arranged to exerttheir actuating force on opposite sides of a common crank-pin throughseparate piston-rods and connections, so as to produce in effect adouble-acting engine.

The object of my invention is to provide an improved construction inengines of the character referred to; and it consists in the matterhereinafter set forth, and particularly pointed out in the appendedclaims.

In the accompanying drawings, showing my improvements as embodied in acompound engine of the vertical tandem type, Figure 1 is a sideelevation of the engine. Fig. 2 is a sectional elevation taken on line 22 of Fig. 1. Fig. 3 is a similar view on line 3 3 of Fig. 2. Figs. 4 and5 are horizontal sections on lines 4 4 and 5 5, respectively, of Fig. 3.Fig. 6 is a sectional elevation of one form of such devices foradjusting the valve-ring. Fig. 7 is a plan view thereof. Fig. 8 is adetail elevation of another form of such devices for adjusting thevalve-ring. Fig. 9 is a plan detail thereof. Fig. 10 is a verticalsection of my improved engine with its valves arranged somewhatdifferently from the form previously shown. Figs. 11 and 12 arehorizontal sections on lines 11 ll and 12 12 of Fig. 10. Fig. 13 is adetail of the lowpressure valverod used in this instance.

A designates a cast-iron base provided with bearings a a, within whichthe crank-shaftB is horizontally journaled, the base and bearings beingdivided on a horizontal plane through the axis of the shaft to permitthe insertion of the latter. Preferably the base is Serial No. 515,954.(No model.)

parts will be constantlylubricated, the bearings a in this case beingprovided at their outer ends with packing-boxes a to prevent leakage ofoil through thesame. The lowpressure cylinder C is bolted directly tothe top of the base A and is left open atits lower end, but is closed atits upper end by a head or diaphragm C, herein shown made as a separatepart and consequently removable. The high-pressure cylinder D is boltedupon the end of the low-pressure cylinder C and is likewise open at itslower end, while closed at its upper end by a head D, in this instancecast integral with the cylinder; An ordinary lagging D is shown assurrounding the cylinder D, and inserted between it and the outer wallof the cylinder a suitable non-conducting packing D is applied, the sametending to maintain a high temperature in the cylinder-walls.

E designates the low-pressure piston, from the lower side of which apiston-rod E leads downwardly to a rigidly-attached cross-head in theform of a cylindric piston F. Said piston F reciprocates within acylinder G, which is supported within the base A by transversediaphragms A and A The cylinder G is in this instance made as a separatepart or casting, having bearing portions 9 on its exterior adapted tofit within suitable apertures in the diaphragms A and A and has a flangeg at its upper end upon the diaphragm A and through which stud-bolts gare passed to secure the cylinder in place.

H designates the high-pressure piston, and H its piston-rod, whichlatter extends downwardly through a stuffing-box c in the cylinder-heador diaphragm C and through a suitable axial bore in the low-pressurepiston E and its piston-rod E and is provided at its lower end with across-head H located within the hollow interior of the piston F. Thecross-head H is herein shown as forged integral with the piston-rod Hand comprises two depending parallel arms h, which rigidly engage theopposite ends of atransverse crosshead pin H From the cross-head pin H aconnecting-rod I extends downwardly to the crank-pin B and is providedwith a bearingblock I, engaging the lower side of the said made to forman inclosure which may be kept crank-pin. The connecting-rod I is hereinpartially filled with oil, by which the working bearing-brass I restingon the upper side of the cross-head pin H between the arms h, and thetwo depending ends 2'' of which pass through the lower bearing block orbrass I and are secured by nuts t on their lower ends.

Within the cross-head or piston F on either side of the pin H and inaxial alinement therewith are rigidly secured two cross-head pins F, theinner ends of which are pivotally engaged by the two bearing-brasses jjof a forked connecting-rod J, which extends downwardly between the sidesof the connectingrod I and is provided with a bearing-block J, engagingthe upper side of the crank-pin B. The inner ends of the pins F areherein shown as supported against upward deflection by interiordepending lugs f of the piston F, which engage the upper surface of saidpins, so as to hold the same from upward movement. The upperbearing-brasses j of the connecting-rod J are provided with slots j,through which said lugs f pass, said slots being made of sufficientwidth to avoid interference between the lugs and brasses in theoscillatory movement of said rod J. Setscrews f are also herein shownfor the purpose of locking the pins F rigidly in place.

Steam is admitted to the high-pressure cylinder at the bottom thereofand acts on the lower face only of the high-pressure piston. It is thenexhausted into the upper part of the low-pressure cylinder and acts onthe upper face onlyof the low-pressure piston. Normally, therefore, theonly strain on the highpressure connections is the upward pull of thehigh-pressure piston, while the only strain on the low-pressureconnections is the clownward thrust of the lowpressure piston. For thepurpose, however, of preventing the highpressure piston from droppingdown by its own weight and the weight of its connections when the engineis not in operation the low pressure connecting-rod J is furtherprovided at its upper end with a central bearing por tion J thebearing-brass 7' of which engages the lower side of the cross-head pin Hbetween the arm h of the cross-head and between the sides of theconnecting-rod I. Said brass j may be conveniently bored out at the sametime as the brassesj and is not designed to sustain any pressure beyondthat due to the weight of the high-pressure parts when the engine isidle, as hereinbefore stated.

One form of valve mechanism for controlling the action of the steam inthe manner described (see Figs. 2, 3, 4L and 5) comprises an annularseries of port-openings d in the side wall of the cylinder D near thelower end thereof, a similar series of ports 0 in the side wall of thecylinder 0 near the top thereof, and a series of ports 0 extendingthrough the diaphragm C and serving to afford direct connection betweenthe high and low pressure cylinders. The ports d lead inward from anannular passage cl, cored in the wall of the cylinder D and suppliedwith steam by a suitable pipe (1 and the ports 0' lead out wardly intoan annular passage 0 cored in the wall of the cylinder 0, and whichdischarges into an exhaust-pipe c. The inletports are controlled by anannular valve-ring K, having apertures to correspond with said ports d,and the exhaust-ports c are controlled by a similar ring-valve L, havingopenings Z, corresponding with said exhaust-port 0'. Both of said valvesare, as a convenient construction, rigidly connected together and areoscillated through suitable connections by a common eccentric B fixed onthe shaft B. The rigid connection between the valve-rings is in thisinstance accomplished by screws 1', engaging horizontal flanges K and L,respectively, of the valve-rings K and L and passing through slots 0 inthe diaphragm O. Said slots are made long enough to permit the fulloscillatory movement of the valve-rin gs. The diaphragm O is in thisinstance shown as countersunk into the upper end of the cylinder 0 andis clamped between the same and the lower end of the cylinder D by meansof the bolts D which secure the two cylinders together, the outer marginof the diaphragm being provided with apertures through which said boltsI) pass, so that it is positively held against rotation. The valve-ringL is in this instance seated within an annular groove turned in theupper end of the wall of the cylinder which separates its interior fromthe annular passage 0 said wall being thus divided at this point intoinner and outer parts 0 and 0 respectively, between which the valve-ringL is seated and through which the ports 0 are cored. The lower edge ofthe valve-ring L rests upon the bottom of the grooves between the walls0 and c and its upper surface and flange L engage the under surface ofthe diaphragm O.

The ports 0 which afford connection between the high and low pressurecylinders, are controlled by a circular valve-plate M, placed directlybeneath and in contact with the under surface of the diaphragm G andprovided with ports m, corresponding to the ports 0 Said plate M isrotatively supported upon a stationary plate G which is also providedwith port-openings 0 forming a part or continuation of the ports 0 Theplate 0 rests at its outer edge upon the inner part c of the groovedwall of the cylinder and fits closely within the valve-rin g L andbeneath the flange L thereof. The central portion of the plate 0 isformed in its upper surface with a circular boss a", which projects upthrough a closely-fitting circular aperture in the valve-plate M and issecured to the lower surface of the diaphragm O by screw-bolts 0 Asherein shown, said plate 0 also forms the cover of the stuffing-box 0,through which the piston-rod H reciprocates, the body of saidstuffing-box being formed within the diaphragm O. The valve-plate M isin this instance operated simultaneously with the valve-rings K and L bybeing rigidly connected therewith. Such connection is herein shown asconveniently provided by making the valve-plate M of suitable diameterto closely fit within the flange L of the valvering L and making suchdiameter just equal to that of the circle upon which theconnecting-screws Z are arranged, opposing semicircular recesses beingprovided in the inner margin of the flange and outermargin of the plateto form the apertures through which said screws are passed. Each of thescrews Z will thus obviously act as a key to secure the ring and plateagainst relative rotation.

The several port and valve openings are so arranged that theadmissionports d and exhaust-ports 0 will be open at the same time, orduring the upward stroke of the pistons, while the ports 0 which connectthe two cylinders will be opened alternately therewith, or during thedownward stroke of the pistons. The controlling of all said ports in theforegoing construction will thus be accomplished by what amounts to asin gle-moving part.

The connections for oscillating the valverings K and L from theeccentric B as herein shown, are constructed as follows: 0 designates ahorizontal recess provided in the wall of the cylinder 0 at one side ofthe annular passage 0 within which a valve-rod L is adapted toreciprocate in close proximity to the valve-ring L, said valve-rod beingoperatively connected with the valve ring by means of pivotal links ZThe inner end of said rod L is shown as supported within a closed sleeve0 provided in one end of the recess 0 and said valve-rod extends outthrough a suitable stuffing-box 0 at the other end of said recess. Theouter end of the valve-rod is connected by links 'n with the arm n of anoscillating rock-shaft N,journaled to the side of the engine-frame, saidrock-shaft being oscillated by means of a rigid arm M, with which theend of the eccentricrod B is pivotally connected.

The flange K of the valve-ring K rests upon the top surface of thediaphragm O and affords an ample bearingsurface for said valve. In thisinstance also and as a further improvement I have provided an automaticcut-oft valve in the form of a ring-valve O, surrounding the valve K andriding upon the flange K thereof. Said valve may have its movementcontrolled by any desired form of governing device, but is in thisinstance operated from the eccentric p of a shaft-governor P of anyusual or preferred type. The valve-ring O is provided with apertures 0,corresponding to the apertures 7a of the ring K, and will operate inrelation thereto in the manner common to all riding cut-off valves ofthe same general type. The connections shown in this instance foroperating the rid-. ing cut-off valve 0 from the eccentric p aregenerally similar to the connections hereinbefore described between thevalve-ring L and eccentric l3 and comprise a reciprocatory valve-rod 0,located in a horizontal recess D provided in the wall of the cylinder Dat one side of the annular passage d thereof, said rod being connectedwiththe valvering 0 by pivoted links 0. The inner end of the valve-rod Ois supported within a closed sleeve 01*, provided in one end of therecess D and said valve-rod extends out through a suitable stuffing-boxd at the other end of said recess. The outer end of the valve-rod isconnected by links (1 with a radial arm q of a rock-shaft Q, journaledon the side of the cylinder 0, said shaft being oscillated by a radialarm (1 with which the end of the eccentric-rod p is pivotally connected.

In Figs. 6 and 7 I have shown a means by which the valve-ring L may beadjusted and any wear occurring thereon provided for. In thisconstruction the valve-ring is radially divided at one point and isprovided in its vertical flange with a V- shaped slot Z Within said slota wedge-shaped block Z is adapted to be moved vertically by a screw-boltZ the head Z of which rests in a recess at the top of the ring. Byturning the screw Z the wedge Z may be drawn farther into the slot Z andwill obviously force the adjacent ends of the ring apart and enlargeitscircumference, so as to take up any wear which may have occurred on itsouter face.

In Figs. 8 and 9 I have shown aconvenient device for adjusting theriding cut-off valve 0. In this construction the valve-ring is di videdat one point, at which its ends are made to overlap, as shown in Fig. 9.Lugs o are provided on each of the overlapping ends, and a bolt 0provided with adjusting-nuts 0 serves to adj ustably connect said lugs,and consequently the two ends of the ring. The circumference of the ringmay thus be increased or diminished, as desired, to secure the properadjustment or make up for any wear.

A valve mechanism somewhat modified from that just described and in manyrespects superior to it is illustrated in Figs. 10, 11, 12, and 13. Insaid figures, O designates the diaphragm which separates the high andlow pressure cylinders. Said diaphragm is countersunk into the adjacentends of both the cylinders and is clamped between the same by means ofthe bolts D, which secure the two cylinders together. The high-pressuresteam-ports e in this construction are located entirely within the bodyof the diaphragm O and extend in curved form beneath the lower edge ofthe wall of the high-pressure cylinder, so as to connect the interior ofthe latter with the annular live-steam passage 01.

K designates the steam-valve, which is a plain cylindric ring restingupon the upper surface of the diaphragm as a seat and provided withport-apertures k, corresponding with the ports 0 Said valve K isessentiallya simple gridiron-valve of annular form and fits looselywithin the lower part of the recess 01, the contact of its under surfacewith the top of the diaphragm C being solely depended upon to afford asteam-tight joint. Consequently no adjusting device for the ring isrequired, and all danger of its binding by reason of the unequalexpansion of the parts is avoided. The riding cut-off valve is omittedin this instance and the valve K itself operated through the medium ofan automatic cut-off governor by means of connections substantiallysimilar to those before shown for operating the riding cut-off valve 0.Obviously, however, the valve K may be operated as a main valve and aseparate riding cut-0E valve employed in connection therewith, asbefore, if so desired.

The lower part of the diaphragm C is formed by a separate plate 0 whichrests at its outer edge upon an annular shoulder 0 of the wall of thecylinder 0 and at its middle portion is secured to the body 0 of thediaphragm by means of the screw-bolts 0 The upper face of the plate 0 isrecessed to receive the lowpressure admission-valve M. Said valveconsists of a single flat plate of annular form inserted bet-ween theupper and lower sections 0 C of the diaphragm and provided withport-apertures m,c0rrespondin g with the ports 0 which extend throughthe diaphragm, as before, to afford communication between the twocylinders. The upper ends of the ports c are in this instance madecoincident with the inner ends or the high-pressure steamports 0 Theinner wall of the cylinder 0, which separates its interior from theannular exhaust-passage c terminates in this instance at a point somedistance below the plate 0 and the cylinder is bored out above thispoint to receive an annular exhaust-valve L Said valve L consists of aplain cylindric ring, similar to the hi gh-pressure valve K providedwith exhaust-ports Z opening outwardly and downwardly from the top andupper inner surface thereof and cooperating with correspondingport-openings 0 leading into the exhaust-passage 0 To reduce theclearance the lower diaphragm-plate O is provided at its outer edge witha depending annular flange 0 the bottom of which engages the top of thevalve L said flange being provided around its lower inner margin with aseries of notches a, corresponding with the ports Z and aifording a freeentrance to the same.

As herein shown, the low-pressure inlet and exhaust valves are arrangedto be operated simultaneouslyfrom the eccentric 13 by means similar tothat before described and including a valve-rod L reciprocating in atangential recess 0 of the cylinder 0. This rod L in this instancepasses through a groove 0 out in the upper surface of the lowerdiaphragm-plate C The middle portion of the rod is made rectangular andis provided with an elongated slot Z A thin flat lug Z projects into theslot at one end thereof and is provided with a vertical pin Z the upperand lower ends of which pivotally engage the adjacent ends of two linksL The latter are made sufficiently narrower than the slot to oscillatefreely within the same, and their combined thickness issubstantiallyequal to the thickness of the rod L at this point, their pivoted endsbeing recessed on their adjacent faces to receive the lug I betweenthem.v The free ends of the links L and L by a screw bolt or pin Z whichengages suitable apertures in each of said parts and passes freelythrough a curved slot 0" in the plate C beneath the recess 0construction as the rod L is reciprocated by its connection with the camB the valve-rings M and L will obviously be operated to open and closethe low-pressure inlet and exhaust ports, the relative arrangement ofthe portopenings being such that the exhaust and steam ports are openedat alternate intervals. The end of the valve-rod L, which is connectedwith the cam B extends out of the recess 0 through a stuifing-box 0 asbefore described. At its other end, however, the rod is herein shown asprovided with a piston-head Z fitting within a short horizontal cylinder0 formed at the end of the recess 0 opposite the stuffing-box 0 Steam isadmitted to the cylinder 0 through a pipe 0 in the head thereof andexerts a continuous pressure on the valve-rod, by reason of which thedirection of pressure is maintained constant throughout all the bearingsof the connections between the valve-rod and cam B thus preventing anylost motion or backlash in such bearings no matter how worn they maybecome.

One great advantage of the construction thus described is that thearrangement of the port-openings is such as to almost instantly drainoff any water of condensation which may form in either cylinder. Waterin the high-pressure cylinder will run naturally into the ports 0 and cand through the latter into the low-pressure cylinder, while waterformed or collected in the low-pressure cylinder will be swept up by thelow-pressure piston to the top of the cylinder and will flow off theedges of the piston through the exhaustport openings l and 0 into therecess or exhaust-passage 0 To facilitate the flow of water from the topof the piston, the upper surface of the latter is herein shown as madeof slightly conical form, so that any water collecting upon it runsnaturally toward its outer margin, the under surface of thediaphragm-plate 0 being correspondingly hol lowed out, so as not toincrease the necessary clearance-space.

As a further improvement for insuring the drainage of the low-pressurecylinder the latter is herein shown provided on its inner surface nearthe lower end of the cylinder witha plurality of vertical grooves 0 theupper ends of which terminate slightly above the upper margin of thelow-pressure piston are pivotally connected with the valves M By this ny when in its lowermost position and which extend at their lower ends tothe lower margin of the cylinder. Thus any water which may havecollected on the piston during its downward stroke will be dischargedthrough the grooves c into the cavity of the engine-frame above thediaphragm A, from whence it may be drawn off through a drain-pipe 0 Noappreciable loss of efficiency can occur by reason of the grooves 0since the latter are uncovered by the piston only for an instant in eachstroke, and that just at the beginning of the exhaust stroke, so thatthe discharge through them merely constitutes in effect an auxiliaryexhaust. Obviously, also, said grooves may be employed in any similartype of single acting vertical engine and are herein shown as applied toboth the forms illustrated.

. One great advantage of engines of the type under consideration, 1'.e., in which two single-acting pistons are arranged to exert theiractuating force on opposite sides of a common crank-pin through separateconnec tions therewith, lies in the fact that the steam-pressure on eachpiston always tends to maintain the direction of pressure constant inthe bearings of its connections with the crank-pin, so that no matterhow long the engine may be run without adjustment or how great the wearin said bearings there can be no lost motion, and consequently nopounding or lack of smoothness in its operation. The inertia of eachpiston and its connected reciprocating parts, however, tends at certainpoints in the strokes to reverse the direction of thrust, such tendencybeing greatest toward the end of the return or exhaust stroke, when thesteam has been expanded to a minimum of pressure, and being particularlyliable to be present in high-speed engines and engines in which thereciprocating parts are made relatively very heavy. For example, in theengine herein set forth the inertia of the low-pressure piston E and itsconnected reciprocating parts tends during the last half of the upwardstroke to maintain in said parts the maximum speed acquired at themiddle of the stroke, and consequent-1y to carry the cross-head pin Faway from its normal engagement with the lower half of the bearing-brassJ 2 of the connecting-rod J and to carry the lower end of saidconnecting-rod away from its normal engagement with the upper surface ofthe crank-pin B. In a similar manner the inertia of the piston H andconnected reciprocating parts tends during the latter part of itsdownward stroke to cause a separation between the bearing-block J andthe lower sideof cross-head pin F So, also, at the beginning of theactive stroke of each piston if the steam-supply should be withheld bythe action of the automatic governor or for any other reason a similarseparation of the bearing pins and brasses would tend to be produced.

A principal feature of my present invention consists in the employmentof pneumatic cushioning devices for overcoming the inertia of thereciprocating parts and maintaining the direction of pressure constantin all of the bearings in the connections between each of the pistonsand the crank-pin independently of the usual steam-cushion effected byproviding for the early closing of the exhaust parts. In this instance Iemploy both a vacuum and air-compression for the purpose stated, thevacuum being employed in connection with the high-pressure piston an dthe air-compression devices with the lowpressure piston, al though,broadly considered, this arrangement might be reversed or bothpistons supplied with the same type of cushioning device of either kind.

The independent cushioning of the lowpressure piston is eltected by thecross-head F, which, as hereinbefore stated, is made in the form of thepiston working within the cylinder G. The upper end of said cylinder isclosed by a suitable head or diaphragm G, secured in place by thestud-bolts g which are made of proper length for this purpose. Asuitable stuffing-box Gr provides for the passage of the piston-rod Eand prevents leakage about the same. Air is admitted to the cylinderwhen the piston is at the lowermost limit of its stroke through openingsg in the side walls of the cylinder near the lower end thereof and iscompressed so as to overcome the inertia of the reciprocating parts andto maintain constant the direction of pressure in the bearings of thelow-pressure connections. \Vith such construction the work done incompressing the air on the upstroke of the piston will be substantiallyall given out on the downstroke thereof, since at that time the pressureof air on the cross-head would be added to the pressure of steam on thepiston in imparting to the crank-shaft its actuating impulse.Consequently there will be no loss of power by reason of the employmentof such auxiliary air cylinder and piston.

The vacuum device for overcoming the inertia of the high-pressure pistonand connections is herein shown as conveniently provided by making theupper part of the highpressure cylinder air'tight, except forareliefvalve D, which permits the escape of air from the cylinder, butprevents the admission of air thereto. \Vith this construction the firstfew strokes of the piston H will obviously operate to expel all the airor vapor which may have accumulated in the upper part of the cylinder,and any leakage of air or vapor past the piston-packin g occurringthereafter at any time will be expelled in a like manner, so that apractically perfect vacuum will be formed and maintained in the top ofthe cylinder as soon as the engine is started. The suction of the vacuumthus provided, or, in other words, the atmospheric pressure acting inconsequence of the vacuum, will obviously exert a continuous upwardpressure on the high-pressure piston, tending to raise the same and toconstantly maintain in the bearings of the connections with thecrank-pin the same direction of pressure as that produced by the steamadmitted beneath the piston.

Any predetermined degree of compression may obviously be had in theair-cylinder G by properly proportioning the size of the clearance-spaceat its upper end, and with the same degree of compression a greater orless cushion will be provided for the low-pressure cylinder, accordingas the air-cylinder is made of greater or less diameter. The properproportions of the parts will ordinarily be provided for when the engineis designed, leaving any slight variations in the amount of suction 'tobe had by varying the point of exhaust-closure in the ordinary manner.

The effective suction of the vacuum above the high-pressure piston uponthe latter can obviously never exceed the pressure of the atmosphere,and the amount of cushion provided thereby will therefore be fixed bythe size of said piston. Any regulation of the total cushion of thehigh-pressure piston must consequently consist in adjusting theexhaustclosure to add to the vacuum-pressure in greater or less degree,as desired.

An important feature of my invention is embraced in the constructiondescribed, wherein the cylinders are separated by a diaphragm havingports which directly connect the cylinders and which contains only themoving part of the valve necessary for opening and closing said ports inthe diaphragm, in connection with'inlet-ports for the high-pressurecylinder, separate from the diaphragm ports, in the end of said cylinderadjacent to the diaphragm and exhaust ports for the low-pressurecylinder, also made separate from the diaphragm-ports and similarlylocated at the end of the cylinder adjacent to the said diaphragm. Thisconstruction and arrangement of the diaphragm and adjacent cylinderports has the important advantage of afiording a direct passage forsteam from the high to thelow pressure cylinder practically without anyclearance-space between the two cylinders, the clearance-space in theconstruction employed being only that arising from the necessarythickness of the diaphragm at either side of the valve therein. Ageneral advantage afforded by such direct communication between the highand low pressure cylinders is that it, in effect, brings the twocylinders into open communication with each other when the valve in thediaphragm is open, by reason of the relatively large area of ports whichmaybe provided in a diaphragm such as is shown, thus giving perfectfreedom of movementto the steam as it expands from the high into the lowcylinder and thereby enabling the engine to run with increased speed andeconomy,while afifordin g an exceedingly cheap and simple constructionin the engine as a whole.

My improved valve mechanism described is obviously of value insituations analogous to that in which it is herein placed independentlyof the other structural features set forth. Furthermore, my pneumaticcushioning devices may obviously be employed on engines of this andsimilar types without regard to the style of valve mechanism usedthereon. As a complete machine, however, an engine provided withtheprincipal or all of the improvements hereinbefore referred topossesses many advantages, and is accordingly herein claimed.

I claim as my invention 1. In a compound engine the combination withsingle-acting high and low pressure cylinders arranged end to end andprovided at their adjacent ends with steam and exhaust ports, andpistons within the cylinders, of piston-rods and connections atfordingseparate connections between said pistons and a common cranlcpin, anair-cylinder provided with a piston which is rigidly connected with thepiston of one of the steam-cylinders, the other cylinder being providedwith a vacuumspace for controlling the inertia of the piston of saidcylinder, substantially as described.

2. In a compound engine having high and low pressure cylinders attachedto each other end to end and pistons within the cylinders,

of piston-rods and connections affording separate connection betweeneach piston and a common crank-pin, said cylinders being provided withsteam inlet and exhaust ports at their adjacent ends, an air-cylinderprovided with a piston which is rigidly connected with the piston of thelow-pressure cylinder, the said high-pressure cylinder being closed atits outer end to provide a vacuum-space for controlling the inertia ofthe piston in said cylinder and connected parts, substantially asdescribed.

3. In a compound engine the combination with high and low pressurecylinders arranged end to end and separated by a partition or diaphragmprovided with ports which afford direct communication between thecylinders,

said cylinders being provided with inlet and exhaust ports at theiradjacent ends, and pistons, within the cylinders, of piston-rods andconnections affordin g separate connection between the said pistons anda common crankpin, an air-cylinder provided with a piston which isrigidly connected with the piston of one of the steam-cylinders, theother of said steam-cylinders being provided at its end remote from thatat which the ports thereof are located with a vacuum-space forcontrolling the inertia of the piston of said cylinder, substantially asdescribed.

at. The combination with high and low pressure steam-cylinders arrangedend to end and separated by a partition or diaphragm having ports whichafford direct communication between the cylinders, said cylinders beingprovided with inlet and exhaust ports at their adjacent ends, valvescontrolling said ports,

pistons in the cylinders, piston-rods and connections affording separateconnection between each piston and a common crank-pin, and anair-cylinder provided with a piston which is attached to the piston-rodof the lowpressure cylinder and forms the cross-head thereof, the outerend of the said high-pressure cylinder being closed and provided with anoutwardly-dischargin g air-valve, substantially as described.

5. In a compound engine, the combination with high and low pressurecylinders arranged end to end and separated by a partition or diaphragmprovided with ports affording direct communication between thecylinders, the said high-pressure cylinder being provided with anannular steam-supply passage located exterior to its side wall and withsteam-inlet ports leading from said supplypassage to the interior of thecylinder at points adjacent to the outer margin of said diaphragm andthe low-pressure cylinder being similarly provided with an annularexhaust-passage exterior to its side wall, and with exhaust-portsleading from points adjacent to the outer margin of the diaphragmoutwardly to said exhaust-passage, and valves controlling the saidports, substantially as described.

6. In a compound engine the combination with high and low pressurecylinders arranged end to end and separated by a partition or diaphragmcontaining ports which afford direct communication between thecylinders, the said high-pressure cylinder being provided with anannular steam-supply passage located exterior to its side wall and withsteam-inlet ports leading from said supplypassage to the interior of thecylinder at points adjacent to the outer margin of said diaphragm andthe low-pressure cylinder being similarly provided with an annularexhaust-passage exterior to its side wall, and with exhaust-portsleading from points adjacent to the outer margin of the diaphragmoutwardly to said exhaust-passage,valves controlling said ports, pistonsin the cylinders, and piston-rods an d connections affording independentconnection between said pistons and a common crank-pin, substantially asdescribed.

7. In a compound engine the combination with high and low pressurecylinders placed end to end and separated from each other by a partitionor diaphragm provided with ports which afford direct communicationbetween the cylinders, the said high-pressure cylinder being providedwith an annular steam-supply passage located exterior to its side walland with steam-inlet ports leading from said supply-passage to theinterior of the cylinder at points adjacent to the outer margin of saiddiaphragm and the low-pressure cylinder being similarly provided with anannular exhaust-passage exterior to its side wall and with exhaust-portsleading from points adjacent to the outer margin of the diaphragmoutwardly to said exhaust-passage, annular valves controlling saidexhaust-ports, and a flat annular valve controlling the ports in saiddiaphragm, said valves being rigidly connected with each other and beingmoved simultaneously, substantially as described.

8. In a compound engine, the combination with high and low pressurecylinders arranged end to end and separated by a diaphragm or partitioncontaining ports which afford direct communication between thecylinders, the said high-pressure cylinder being provided with anannular steam-supply passage located exterior to its side wall withsteam-inlet ports leading from said supply-passage to the interior ofthe cylinder at points adjacent to the outer margin of said diaphragm,and the lowpressure cylinder being similarly provided with an annularexhaust-passage exterior to its side wall, and with exhaust-portsleading from points adjacent to the outer margin of the diaphragmoutwardly to said exhaust-passage, valves for controlling the saiddiaphragmports and the exhaust-ports, and means embracing an automaticcut-01f mechanism applied to operate the valves which control theinlet-ports of the high-pressure cylinder, substantially as described.

9. In a compound'engine, the combination with high and low pressurecylinders arranged end to end and separated by a partition or diaphragmprovided with ports which afiord direct communication between thecylinders, the said high-pressure cylinder being provided with anannular steam-supply passage located exterior to its side wall and withsteaminlet ports leading from said supply-passage to the interior of thecylinder at points adjacent to the outer margin of said diaphragm, andthe low-pressure cylinder being similarly provided with an annularexhaust-passage exterior to its side wall, and with exhaustports leadingfrom points adjacent to the outer margin of the diaphragm outwardly tosaid exhaust-passage, annular valves controlling said ports, saiddiaphragm-valves and exhaustvalves being rigidly connected with eachother, and means embracing an automatic cut-01f mechanism for actuatingthe valve by which the inlet-ports of the highpressure cylinder arecontrolled,substantially as described.

10. In a compound engine, the combination with high and low pressurecylinders arranged end to end and separated by a partition or diaphragmcontaining ports which afford direct communication between thecylinders, the said high-pressure cylinder being provided with anannular steam-supply passage located exterior to its side wall and withsteam-inlet ports leading from said supply-passage to the interior ofthe'cylinder at points adjacent to the outer margin of said diaphragm,and the low-pressure cylinder being similarly provided with an annularexhaust-passage exterior to its side wall, and with exhaust-portsleading from points adjacent to the outer IIO margin of the diaphragmoutwardly to said exhaust-passage and a fiat or plate valve ap-"exterior to its side Wall and with steam-inlet ports leading from saidsupply-passage to the interior of the cylinder at points adjacent to theouter margins of said diaphragm, and the low-pressure cylinder beingsimilarly provided with an annular exhaust-passage exterior to its sidewall, and with exhaust-ports leading from points adjacent to the outermargin of the diaphragm outwardly to said exhaust-passage and annularvalves controlling said ports, said annular valves controlling thediaphragm-ports and exhaustports being rigidly connected with each otherso as to move together in the operation of the same, substantially asdescribed.

12. In a compound engine, the combination with high and low pressurecylinders arranged end to end and separated from each other by apartition or diaphragm containing ports which afford directcommunication between the cylinders, the said high-pressure cylinderbeing provided with an annular steam-supply passage located exterior toits side wall and with steam-inlet ports leading from saidsupply-passage to the interior of the cylinder at points adjacent to theouter margins of said diaphragm, and the low-pressure cylinder beingsimilarly provided with an annular exhaust-passage exterior to its sidewall, and with exhaust-ports leading from points adjacent to the outermargin of the diaphragm outwardly to said exhaust-passage, a circularvalve-plate applied to control the ports of said diaphragm, a valve-ringapplied to control the exhaust-portsof the low-pressure cylinder, and avalve-ring applied to control the steam-inlet ports of the high-pressurecylinder, said valve-rings of the diaphragm and exhaust ports beingrigidly connected with each other whereby they are moved together in theoperation of the engine, substantially as described.

13. The combination with high and low pressure cylinders arranged end toend and separated by a partition or diaphragm containing ports whichafiord direct communication between the cylinders, the saidhigh-pressure cylinder being provided With an annular steam-supplypassage located exterior to its side wall and with steam-inlet portsleading from said supply-passage to the interior of the cylinder atpoints adjacent to the outer margin of said diaphragm, and thelow-pressure cylinder being similarly provided with an annularexhaust-passage exterior to its side wall, and with exhaust-portsleading from points adjacent to the outer margin of the diaphragmoutwardly to said exhaustpassage, valve-rings controlling said severalsets of valve-ports, said valve-rings of the diaphragm and exhaust portsbeing rigidly connected with each other, and means for actuating theseveral valve-rings comprising a reciprocating rod which passes throughthe said exhaust-passage and is connected with the valve-ring therein,and means operated from the crank-shaft of the engine by whichreciprocatory motion is given to said rod, substantially as described.

14. The combination with high and low pressure cylinders arranged end toend and separated by a diaphragm containing steam-ports, thehighpressure cylinder being provided with an annular steam-inlet passageand with annularly-arranged steam-ports at its end adjacent to the saiddiaphragm, and the low- 1 pressure cylinder being provided with anannular exhaust-passage and with annularlyarranged exhaust-ports at itsend adjacent to said diaphragm, of an annular valve-plate applied tocontrol the ports in said diaphragm, a valve-ring applied to control thesaid exhaust-ports, said valve-ring being attached to the valve-plate ofthe diaphragm-ports by means of a stud extending through a slot in thesaid diaphragm, substantially as described.

15. The combination with two cylinders arranged end to end and providedone with steam inlet and the other with exhaust ports located at theiradjacent ends, of a diaphragm separating the cylinders and provided withsteam-ports, a valve-plate for. controlling the ports in the diaphragm,and valve-rings for controlling the steam inlet and exhaust ports, saiddiaphragm being provided with two plates located one at each side of thevalveplate, whereby the latter is held in place under pressure fromeither direction, substantially as described.

16. The combination with two cylinders arranged end to end and providedone with steam inlet and the other with exhaust ports located at theiradjacent ends, of a diaphragm separating the cylinders provided withsteamports, and consisting of two plates, one of which is engaged at itsedges withthe adjacent ends of both cylinders, and the other of which isengaged at its edges with the end of one of the cylinders and is securedto the central part of the first plate, a circular valveplate locatedbetween the said plates of the diaphragm, a valve-ring for controllingthe said exhaust-ports, said valve plate and ring being rigidlyconnected together to move simultaneously, substantially as described.

17. In a single-acting compound engine, the combination with high andlow pressure cylinders arranged end to end and separated by a partitionor diaphragm containing ports which afford direct communication betweenthe cylinders, said cylinders being respectively provided at theiradjacent ends with the annular exhaust-passage thereof and operativelyconnected valves controlling the low-pressure steam and exhaust ports,substantially as described.

In testimony that I claim the foregoing as my invention I aflix mysignature in presence of two Witnesses.

'MILAN O. BULLOCK. Witnesses:

HENRY W. CARTER, ALBERT H. GRAVES.

